Notes on the Second Edition to Emergency Navigation

 This book was first published in 1984, after about 6 years of research on the subject. From then till second edition work began (2007) we have worked continuously in the field of marine navigation and can proudly state that we have not found concept nor technique errors in the book, nor have we found things that should be there that are not—a few new ideas are listed below, the most notable of which (sextant sights from digital photos) was not very viable in 1984.

Please skim through that section to see what is there; it outlines things that have naturally grown outdated during this period, along with sources for the updates. These are mainly related to references and sources that have changed over the years, along with a few new ideas, some tested, some still in the process of testing.

The definitely new approach to studying this subject is online learning. Starpath School of Navigation have developed a series of online courses, one of which is on Emergency Navigation. The framework of this particular course is essentially a “reading group” of this book. We go through it chapter by chapter, with specific practice exercises on the chapter contents, along with group discussions of the materials. It is also a place for mariners—or outdoors travelers of any ilk—to share their experiences and ask questions about the content. The practice exercises transform the text material into more tangible knowledge.

We have added a webpage for the book to post news and updates and related links as they evolve. Please see www.starpath.com/emergencynavbook

—David Burch

Emergency Navigation, Second Edition Updates

(1) The art work has been updated. Though still based on the author's original sketches, much of the lettering has clarified and original stick figures have been replaced by a little man in a sombrero!

(2) There was reference to using Loran and sat nav units for cel nav sight reduction in original. Since GPS has replaced Loran, this technique now required more special care, which has led to the introduction of the topic of ellipsoidal great circle computations.

(3) We have more data and observations of flight patterns to update section on “contrail navigation.” Thanks to neighbor, sailor, and commercial pilot Jay Towne for helping with this.

(4) Added new section on use of polarized sunglasses to find direction to an obscured sun as the Vikings did with sun stones.

(5) Stress practice using internet resources, primarily based on the USNO’s AA department web page.

(6) Add new steering technique example of using distant clouds on the horizon viewed across the beam from sitting in the cockpit. Method noted and tested on 2004 Pac Cup race.

(7) Updated bibliography. Most of the government references have changed. Some books are out of print. Others that were out of print are now available as ebooks.

(8) Update the emergency nav kit, announcing Geoffrey Kolbe's Long Term Almanac. We have also added a Lesson to the online course on how to use this valuable booklet, good till 2050, which also includes the NAO sight reduction tables so it can provide complete fix, compass check, or compute great circle routes.

(9) Note added about David Lewis (1917 to 2002, scientist, adventurer, master mariner, and gentleman, and author of the Forward) who has gone off to sail other seas.

(10) Added notes on a “personal Beaufort Scale,” developed over the intervening years.

(11) Replaced all references to Loran and SatNav with GPS counterpart examples.

(12) Updated declination minutes of Polaris from 48’ to 43’. Added “regiment of the pole” to index. Also the declination of the star Arcturus has changed by 8’ over these 20+ years—so much for the permanence of the fixed stars (although this one star moves much faster than most)

(13) Fixed a couple typos in the figures and captions.

(14) Over the years, the content of this book has been used extensively by Arctic and Antarctic travelers, because compasses do not work near the poles and GPS displays freeze in just a minute or so. Of special interest is the use of the sun compass ideas. We had hoped to add new pictures and stories of these in actual use, but this did not quite happen. These will now go into the online course.

(15) Created and added an analemma that can actually be used for numerical values. This is a graphic figure of much interest made up by plotting the equation of time versus the declination of the sun. See analemma.com. Most such drawings are decorative, but this one can be used. A high res image of it is in the online course.

(16) It has been proposed that the tangent to the horns of a half moon makes a good pointer to due south. We are still studying this to see if we can set some mathematical limits on it. It definitely works in some cases, but in others it does not. We have data in the online course. This method is outlined with its limitations in the new edtion.

(17) There is a new section on obtaining a cel nav fix from the photograph of sun or moon and one other body that shows the horizon. We have discussion of this online with samples. It is very promising. A cell phone picture of the sky can tell you where you are!